Press connections of this type are used between massive carriers and the thin-walled structural components of sheet metal everywhere in machine and automobile building, where there are requirements with respect to low structural height and light-weight construction. The quality of the surface of the structural components of sheet metal is very high, so that chip-removing refinishing operations are not necessary. This has an advantageous effect on the cost of manufacturing.
Examples for uses are bearing rings for needle or roller bearings which are drawn of sheet metal and which can be used without performing a refinishing operation of the rolling surfaces. Further examples are sealing surfaces which are formed by the surface of sleeves after drawing.
As a result of the connection of carrier and sleeve, for example, ducts of media guides are formed. For this purpose, grooves in the surface of carriers are covered by means of the thin-walled structural component, so that laterally delimited ducts are formed on all sides. As a result of this type of arrangement, the complex drilling of, in particular, long lubricating ducts in shafts is avoided.
Bearing rings of radial bearings and sealing sleeves are, as already mentioned, sleeve-shaped, thin-walled structural components of sheet metal by way of the thin walls of which the radial structural height can advantageously be kept as small as possible. Such thin-walled structural components are preferably manufactured inexpensively by cold forming, especially by deep drawing of sheet metal. Thin-walled bearing rings are frequently comparatively non-round as individual components. Therefore, they must be pressed into or onto the bearing seat of the carrier in order to assume the roundness required for roller bearings. In addition, the optimum radial bearing play and the fixed seat of the respective bearing ring are achieved with the press fit.
The respective cylindrical seat for the bearing ring or for the sealing sleeve is achieved by way of functional indentations or indentations caused by manufacturing requirements on the surface of the carrier which are formed, for example, by openings of guides and ducts for liquid or gaseous media or any other recess-like indentation. The pressing forces required for the press fit are relatively high, so that during pressing in of the rings they have the tendency to be upset and to yield radially into the indentations. As a result, the rings deform non-round especially at the indentations.
The sheet metal of the wall sections with which the groove-like or opening-like indentations are covered yields because of the lacking radial support in the area of the indentations during pressing in radially outwardly and during pressing on radially inwardly into the indentations. In addition, the structural components are shrunk into the indentations because of the tensions of the press fit. The contours of the ducts are formed in such a way that non-roundness and other undesirable deviations of shape can occur and, as a result, the piston travel and sealing surfaces become non-round and untight and the rolling surfaces become imprecise.
Therefore, in these arrangements a press fit of the sleeve-shaped structural components with the respective carrier is frequently omitted. Consequently, the non-roundness occurring in the bearing and in the sealing seats and greater operational plays are accepted. The structural components are then secured, for example, by lugs at the appropriate seats.
Thin-walled sleeves are used, for example, as sealing sleeves in gear units with shaft systems which are interlaced, such as in torque converter transmissions or double clutch transmissions. These sleeves seal oil-conducting structures, close openings due to manufacturing requirements, or are used for the targeted supply of lubrication oil. Such sleeves are frequently pressed into cylindrical bores of hollow shafts. It is in this field that the expert is confronted with the above-described problems. In the area of the indentations, deformations and surface defects, at the sealing seats for example, are formed which may lead to losses due to leakages in these media guides.
DE 42 38 147 A1 shows such media guides in an automatic gear unit which are delimited by bearing rings of two roller bearings and are formed at the surroundings thereof. The respective oil guide leads pressure oil to a respective piston cylinder unit of a hydraulically actuatable coupling. As a result of the presence of the roller bearings, a hollow-cylindrical shaft portion of a planetary drive referred to as the carrier of the sleeve-shaped structural component is rotatably mounted in housing sections of the hydraulic couplings of the automatic gear unit.
The first roller bearing has an inner bearing ring and an outer bearing ring, wherein the bearing rings are both formed as hollow-cylindrical sleeve-shaped structural components between which the rolling bodies roll on rolling surfaces. The carrier for the inner bearing ring is a hollow cylindrical section of the housing of the first piston cylinder unit of one of the hydraulically actuated couplings. The carrier for the outer bearing ring is a shaft section in the inner cylindrical hole of which the bearing ring is seated and is rotatable together with the latter about an axis of rotation.
The second roller bearing has an inner and an outer bearing ring with raceways for the rolling bodies which are both sleeve-shaped structural components. The carrier for the inner bearing, which carrier is rotatable about the axis of rotation, is the cylindrical shaft section of the planetary drive. The carrier for the outer bearing ring is a housing of the second piston cylinder unit of one of the hydraulically actuated couplings in the bore of which it is seated.
The inner and outer bearing rings are also constructed as sealing sleeves and oil guiding elements and have additionally sealing surfaces and the rolling surfaces for rolling bodies. Pressure oil is initially conducted to the outer bearing ring of the first roller bearing and to the inner bearing ring of the second roller bearing via ducts in the hollow-cylindrical shaft section. The ducts are located at the outer bearing ring of the first roller bearing and at the inner bearing ring of the second roller bearing.
The outer bearing ring of the first roller bearing has a radial throughopening which is in communication in a manner permeable to oil with one of the ducts of the first oil guide. Through this throughopening, oil can flow from the duct into the interior of the first bearing to the inner bearing ring. The inner bearing ring also has a radial throughopening which is in communication in an oil-permeable manner with a further duct of the first oil guide to the first piston-cylinder unit.
The inner bearing ring of the second roller bearing closes the duct of the first oil guide so that no oil can penetrate from the first oil guide into the second roller bearing. However, the inner bearing ring of the second roller bearing has a radial throughopening which is in communication in an oil-permeable manner with a duct of the second oil guide. In addition, the outer bearing ring of the second roller bearing has a radial throughopening which is in communication in an oil-permeable manner with a further duct of the second oil guide which leads to the second piston-cylinder unit.
The first roller bearing and the second roller bearing are each sealed laterally relative to the surroundings, so that hardly any pressure oil can escape from the respective roller bearing to the surroundings. For this purpose, the outer bearing ring of the respective roller bearing has sealing surfaces against which a respective sealing ring rests.